Method and Apparatus for Performing Activation/Deactivation of Serving Cell in Wireless Communication System Supporting Dual Connectivity

1. A method for controlling activation of a serving cell by a User Equipment (UE) supporting a dual connectivity, the UE communicating with a first node and a second node for the dual connectivity, the method comprising: receiving, from the first node, first information including activation/deactivation indicators of secondary serving cells (SCells) in a first SCell group configured for the UE; receiving, from the second node, second information including activation/deactivation indicators of SCells in a second SCell group configured for the UE; and controlling activation/deactivation states of the SCells in the first SCell group according to the activation/deactivation indicators of the SCells in the first SCell group identified from the first information received from the first node, and controlling activation/deactivation states of the SCells in the second SCell group according to the activation/deactivation indicators of the SCells in the second SCell group identified from the information received from the second node.

2. The method of claim 1 , further comprising: configuring the dual connectivity in which the UE has Radio Resource Control (RRC) connections with the first node and the second node, respectively.

3. The method of claim 1 , wherein the first node is a master evolved NodeB (MeNB), and the second node is a secondary evolved NodeB (SeNB).

4. The method of claim 3 , further comprising: receiving, from the MeNB, a Radio Resource Control (RRC) signal including information of an SCell configuration for the first node and information of an SCell configuration for the second node.

5. The method of claim 4 , further comprising: identifying whether an SCell is in the first SCell group associated with the MeNB or in the second SCell group associated with the SeNB, by using the RRC signal received from the MeNB.

6. The method of claim 3 , further comprising: receiving, from the MeNB, a Radio Resource Control (RRC) signal including a first deactivation timer value for the first node and a second deactivation timer value for the second node to control activation/deactivation status of an SCell, wherein the first deactivation timer value and the second deactivation timer value have different integer values.

7. The method of claim 1 , wherein the first information comprises a Medium Access Control (MAC) control element (CE) having a fixed size of 8 bits, and the second information comprises a MAC CE having a fixed size of 8 bits, wherein each of the MAC CE received from the first node and the MAC CE received from the second node has one reserved bit and seven configurable bits, wherein the seven configurable bits correspond to SCells having SCell indexes 1 to 7, respectively, and wherein a bit of the MAC CE received from the first node having an SCell index i corresponds to an activation/deactivation indicator of an SCell in the first node, and a bit of the MAC CE received from the second node having an SCell index j corresponds to an activation/deactivation indicator of an SCell in the second node, and wherein i and j, which are integers among 1 to 7, have different integer values.

8. The method of claim 7 , further comprising: identifying, by a first Medium Access Control (MAC) scheduler, a bit corresponding to an SCell associated with the first node from the MAC CE received from the first node; and identifying, by a second Medium Access Control (MAC) scheduler, a bit corresponding to an SCell associated with the second node from the MAC CE received from the second node.

9. A method for performing activation/deactivation of a serving cell by a User Equipment (UE) supporting a dual connectivity, the method comprising: receiving, from a master evolved NodeB (MeNB), a Medium Access Control (MAC) control element (CE) including activation/deactivation indicators of serving cells (SCells) associated with the MeNB; receiving, from a secondary evolved NodeB (SeNB), a MAC CE including activation/deactivation indicators of SCells associated with the SeNB; identifying activation/deactivation indicators corresponding to indexes for the SCells associated with the MeNB; controlling activation/deactivation statuses of the SCells associated with the MeNB based on the MAC CE received from the MeNB; identifying activation/deactivation indicators corresponding to indexes for the SCells associated with the SeNB; and controlling activation/deactivation statuses of the SCells associated with the SeNB based on the MAC CE received from the SeNB.

10. The method of claim 9 , further comprising: configuring Radio Resource Control (RRC) connections with the MeNB and the SeNB for supporting the dual connectivity.

11. The method of claim 9 , further comprising: receiving SCell configuration information of the MeNB, from the MeNB, receiving SCell configuration information of the SeNB, from the MeNB, and wherein the SCell configuration information of the MeNB and the SCell configuration information of the SeNB are configured by a Radio Resource Control (RRC) message from the MeNB.

12. The method of claim 9 , further comprising: receiving, from the MeNB, a deactivation timer value for the SCells associated with the MeNB and a deactivation timer value for the SCells associated with the SeNB, wherein the deactivation timer value for the SCells associated with the MeNB and the deactivation timer value for the SCells associated with the SeNB are different.

13. The method of claim 9 , further comprising: identifying which SCell is configured for the MeNB by a MAC scheduler of the MeNB; and identifying which SCell is configured for the SeNB by a MAC scheduler of the SeNB.

14. The method of claim 9 , wherein each of the MAC CE received from the MeNB and the MAC CE received from the SeNB has a fixed size of 8 bits including seven configurable bits and one reserved bit, and the seven configurable bits correspond to SCells having SCell indexes 1 to 7, respectively, and an SCell index i corresponding to an SCell associated with the MeNB and an SCell index j corresponding to an SCell associated with the SeNB have different integer values.

15. The method of claim 9 , wherein: the SCells associated with the MeNB are included in a first serving cell group (SCG), and the SCells associated with the SeNB are included in a second serving cell group (SCG).

16. The method of claim 14 , wherein: a configurable bit corresponding to the SCell index i and included in the MAC CE received from the MeNB is identified as the activation/deactivation indicator of the SCell having the SCell index i; a configurable bit corresponding to the SCell index j and included in the MAC CE received from the SeNB is identified as the activation/deactivation indicator of the SCell having the SCell index j; and wherein a configurable bit corresponding to the SCell index i and included in the MAC CE received from the SeNB is ignored, and a configurable bit corresponding to the SCell index j and included in the MAC CE received from the MeNB is ignored.

17. A method for operating activation/deactivation of a serving cell, by a User Equipment (UE), the method comprising: configuring dual connectivity with a master evolved NodeB (MeNB) and a secondary evoled NodeB (SeNB) for Radio Resource Control (RRC) connection; configuring a secondary serving cell (SCell) group of the MeNB and a SCell group of the SeNB; activating an SCell in the SCell group of the MeNB if an indicator of index of the SCell in the SCell group of the MeNB is set to 1 and deactivating the SCell in the SCell group of the MeNB if the indicator of index of the SCell in the SCell group of the MeNB is set to 0 by checking an activation/deactivation Medium Access Control (MAC) Control Element (CE) message transmitted from the MeNB; and activating an SCell in the SCell group of the SeNB if an indicator of index of the SCell in the SCell group of the SeNB is set to 1 and deactivating the SCell in the SCell group of the SeNB if the indicator of index of the SCell in the SCell group of the SeNB is set to 0 by checking an activation/deactivation MAC CE message transmitted from the SeNB.

18. The method of claim 17 , further comprising: from an activation/deactivation MAC CE message transmitted from the MeNB, identifying indexes of SCells in the SCell group of the MeNB for activation/deactivation of the SCells in the SCell group of the MeNB, and ignoring indexes of the SCells not configured for MeNB; and from an activation/deactivation MAC CE message transmitted from the SeNB, identifying indexes of SCells in the SCell group of the SeNB for activation/deactivation of the SCells in the SCell group of the SeNB, and ignoring indexes of the SCells not configured for SeNB, wherein indexes of SCells are configured per UE.

19. The method of claim 17 , further comprising: setting a first deactivation timer of the SCell group of the MeNB; and setting a second deactivation timer of the SCell group of the SeNB, wherein a value of the first deactivation timer is set in association with the MeNB and a value of the second deactivation timer is set in association with the SeNB, respectively.

20. The method of claim 17 , wherein: an operation of activating an SCell in the SCell group of the MeNB if an indicator of index of the SCell in the SCell group of the MeNB is set to 1 and deactivating the SCell in the SCell group of the MeNB if the indicator of index of the SCell in the SCell group of the MeNB is set to 0, by checking an activation/deactivation MAC CE message transmitted from the MeNB, is operated by a MAC scheduler for the MeNB in the UE; and an operation of activating an SCell in the SCell group of the SeNB if an indicator of index of the SCell in the SCell group of the SeNB is set to 1 and deactivating the SCell in the SCell group of the SeNB if the indicator of index of the SCell in the SCell group of the SeNB is set to 0, by checking an activation/deactivation MAC CE message transmitted from the SeNB, is operated by a MAC scheduler for the SeNB in the UE.